Heat exchange apparatus



. Oct. 8, 1940. A. HOWARD HEAT EXCHANGE APPARATUS Origifia], Filed Feb. 17, 1938 Inventor:

Alan Tgi, b fr 5 y i zt torrwey.

Patented Oct. 8, 1940 UNITED STATES HEAT EXCHANGE APPARATUS Alan Howard, Schenectady, N. Y., assignor to General Electric Company, a corporation of New York Application February 17, 1938, Serial No. 191,057 Renewed September 16, 1939 11 Claims.

The present invention relates to heat exchange apparatus, more particularly, for elastic fluid condensing systems of the surface cooled type. Although not necessarily limited thereto, the invention herein disclosed is especially applicable in systems for condensing the exhaust from elastic fluid engines or turbines utilizing a plurality of similar condenser sections in parallel connection between a common feeder and a common condensate reservoir.

In condensing systems of the type above referred to, differences in operating pressure between the various sections of the condenser, the available drainage head, or other considerations may interfere with the proper drainage of condensate from the condenser and result in imperfect operation of the system. Under these conditions special measures must be taken to insure proper drainage for each section of the condenser.

It is an object of this invention to provide an elastic fluid condensing system in which proper drainage of the various units or sections of the condenser is accomplished by reducing the pressure at the outlet of the common condensate drainage conduit in a novel and eflicient manner.

For a consideration of what I believe to be novel and my invention, attention is directed to the following specification and the claims app'ended thereto taken in connection with the accompanying drawing.

In the drawing Fig. 1 is a perspective view, partly in section; illustrating diagrammatically a heat exchange system embodying my invention and Figs. 2 and 3 are fragmentary elevations, partly in section, illustrating additional modifications of my invention.

Referring to the drawing, It indicates a feeder conduit for conducting elastic fluid, such as steam or mercury vapor, which is to be condensed, from the exhaust of elastic fluid turbines or other elastic fluid apparatus, not shown. A plurality of branch feeders II, I2 and I3 connect the feeder ID to a plurality of individual heat exchanger units such as M, I5 and I6 arranged in parallel. While in this instance I have shown but three such units, it is understood that any desired number of units of any suitable type may be used connected in a similar manner as those shown. It is equally obvious, that instead of employing a number of separate and individual units or sections, a single condenser of a plurality of sections may be used. For purposes of illustration, I have shown the units as being similar in construction and each comprising two sections,

a main condenser section having an upper header chamber I I and an after-cooler section having an upper header chamber IS. A plurality of heat exchange tubes 19 communicate between the upl per headers I1 and the lower headers 20-forming the main condenser section while similar groups of tubes 2| extending between the lower headers 20 and the upper headers l8 form the after-cooler sections. The heat exchanging tubes may be of any suitable design, and may be provided with fins as desired. The upper headers ll, 18 and the lower headers 20 in the present example are mechanically separated and separately manufactured. Obviously the corresponding headers of the different sections may be united and manufactured as unitary structures. Cooling air or other cooling fluid may be passed in contact with the heat transfer surfaces to conduct the heat therefrom. Elastic fluid fed from the conduit I0 into the headers I! passes downward- 1y through the tubes l9 wherein most of the vapors are condensed, the condensate draining into the lower headers 20 from which headers the condensate is discharged through connections 22 and the conduit 23 into the upper portion of the reservoir or hot-well 24. As is well known in the art, the level of condensate in the hotwell is maintained at a substantially constant position by any suitable means, not shown.

The fluid vapor which enters into the lower headers 20 without condensing in the down-pass tubes l9 and the admixed non-condensables pass upwardly through the tubes 2| of the aftercooler sections wherein the condensation of the remaining traces of fluid vapor is completed. The condensate drains from the after-cooler tubes downwardly into the lower headers while the non-condensables are drawn from the upper headers l8 through connections 25 and extraction conduit 26 by a vacuum pump 27 which in turn exhausts the non-condensables to atmosphere through an outlet 28. The vacuum pump 21 may be driven by any suitable means, not shown, connected to the shaft 29 thereof. To insure that a suction will be applied upon each of the headers l8 even in the event that the pressures may be varied in the different individual units, the connections 25 are provided with restrictions or orifices 30. These orifices are of such size to insure the maintenance of a pressure in the conduit 26 substantially below any pressure which might obtain in any of the condenser units.

The elastic fluid in the feeder conduit l0 normally moves with a relatively high velocity, parthe length of the feeder due to the condenser connections and for other reasons, the quantity of elastic fluid supplied to each individual unit may not be the same in each instance. Variations in the flow of cooling fluid across the tubes of the unit may also combine with the above causes further to unbalance the operating pressures obtaining in the different condenser units. The pressure obtaining in the hot-well 24 and at the outlet of the drain conduit 23 is largely determined by the average pressure of the condenser units. Thus, particularly in installations such as in turbine driven locomotives, where the head available for draining the condensers is relatively small, some of the condenser units, that is, those units operating under a pressure below the average pressure, may not drain properly resulting in a complete or partial blocking out of such units and an ineflicient operation of the system as a whole. 7

According to the invention, the proper drainage of the various units of the system is secured by effecting a reduction of the pressure obtaining at the outlet of the common condensate,

draining conduit. As shown in Fig. 1, the connection II extending between the feeder conduit I0 and the upper header II of one of the condenser units, such' as I4, is provided with a restriction or an orifice 3I to limit the flow of elastic fluid into this particular unit to a value substantially smaller than that to the remaining units. Since the units are of substantially the same capacity, a relatively rapid condensation of the comparatively smaller amount of elastic fluid will occur within the unit I4 causing it to operate at a materially lower pressure than the remaining units. This unit is then utilized for reducing the pressure obtaining in the hot-Well by connecting a vent conduit 32 extending from the upper portion of the hot-well 24 with the header I'I substantially as shown. The unit I4 will therefore,

in effect, produce a suction upon the hot-well,

withdrawing fluid vapor therefrom'to reduce the pressure obtaining therein below the operating pressure of the remaining condenser units of the system, such as I5 and IS. A proper drainage of all of the units of the system is thereby secured.

Should any'uncondensed elastic fluid from-one of the other units I5 or I6 be drawn into the conduit 23 by reason of the suction created by the unit I4, a portion of such elastic fluid may be drawn up into the section I4 through the connection 22. To prevent this upward flow of elastic fluid from interfering with the drainage of condensate from unit I4, the connection 22 of this unit is made relatively larger than the corresponding connections of the remaining units need be made to insure proper drainage with this condition obtaining. It is understood that the drain connections of the other units are preferably of such size as is required only for properly conducting the condensate therefrom so that a minimum amount of uncondensed elastic fluid will escape into the conduit 23.

portion of the condenser because of the water seal effected thereby. All of the fluid vapors discharged from the condenser units I5 and I6 through the conduit 23 will be drawn through the vent connection 33 to the upper header ll of the condenser I4 to insure the most eflicient operation of that unit.

Fig. 3 illustrates a further modification in which the condenser unit I4 is drained by a sep-- arate conduit 35 which communicates directly with the hot-well above the water level .therein. In this arrangement, the vent pipe may be dispensed with, the conduit 35 being of such size as to accommodate the flow of condensate from the condenser unit I4 into the hot-well 24, as well as the flow of fluid vapor from the hot-well into the condenser unit. This.connection may provide suflicient venting of the hot-well in the event that the quantity of uncondensed elastic fluid feeding into the hot-well is relatively small.

In the arrangements as shown, the unit I4 is utilized for condensing a certain portion of 'elastic fluid supplied by the feeder I0, the flow thereof to the unit I4 being restricted by a fixed orifice 3| of such a size as determined by the requirements for properly venting the hot-well. In place of the fixed orifice 3I', it is obvious that an adjustable valve may be used so .that the elastic fluid flow therethrough to the unit may be varied as required. Depending upon the operating conditions of the system, the range of adjustments for this valve may vary from .wide open or maximum flow, to closed or minimum flow positions, Moreover, this valve may be arranged for automatic adjustmentin accordance with the pressureobtainin'g in the hot-well by the provision of any suitable means well known in the art. Thus, any constant low pressure may be maintained in the hot-well which will insure the proper drainage of the condenser units of the system. In the event that substantially the entire capacity of the condenser section I4 is required for properly reducing the pressure within the hot-well or reservoir 24 by condensing the vapor withdrawn therefrom. through the connection 32, it is obvious that the orifice or valve will be adjusted substantially to the fully closed position. If the apparatus is to operate with such conditions prevailing, the connection II and the orifice 3| or other flow restricting valve between the condenser section I4 and the header I0 may be dispensed with entirely.

By reason of the venting arrangement disclosed, special precautionary measures need not be taken to limit the leakage of elastic fluid into the hot-well with the condensate, Moreover, the hot-well maybe used as a drainage sump for miscellaneous pieces of apparatus, not shown, included in the elastic fluid system, such as water traps or separators which may be connected to drain as through a conduit 33 into the hot-well. Any fluid vapors and admixed non-condensables passing therethrough with the condensate, will be drawn oIT by the condenser unit I4 and be condensed, or exhausted to atmosphere.

Having described the method of operation of my invention together with the apparatus which I now consider to represent the best embodiment thereof, I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent in the United States is:

1. Elastic fluid condensing apparatus comprising a plurality of condenser units, a header for supplying elastic fluid to said condenser units, a reservoir for receiving condensate from said condenser units, conduit means for connecting said reservoir with each of said units, means for causing at least one of said condenser units to operate at alower pressure than the remaining of said plurality of units and a conduit extending from the inlet of said low pressure unit and communicating with said reservoir for reducing the pressure in said reservoir.

2. A condensing system for elastic fluid including a plurality of condenser units, a header for supplying elastic fluid to said units, a conduit for conducting condensate from said units, means for controlling the-flower" elastic fluid from said header to one of said units, and means communicating with the elastic fluid inlet of said one unit and said condensate conduit for reducing the pressure in said condensate conduit.

3. Condensing apparatus for elastic fluid including a plurality of heat exchanger units, a feeder conduit for supplying elastic fluid to said units, a reservoir for receiving condensate from said units, conduit means for connecting said reservoir with each of said units, means for restricting the flow of elastic fluid from said feeder to one of said units, a conduit communicating with said one unit adjacent the elastic fluid inlet thereof and said reservoir for reducing the pressure in said reservoir.

4. Steam condensing apparatus comprising a plurality of condenser units, each unit including a condensing part and an after-cooler part. a header for supplying steam to said condensing parts of said condenser units, means for withrawing non-condensables from said after-cooler parts, reservoir for receiving condensate from said condenser units. conduit means for connec ing said reservoir with each of said units, means for limiting the how of steam to one of said condenser units to cause said one unit to operate at a lower pressure than the remaining units, and a conduit extending from said reservoir to the condensing part of said one unit for venting said reservoir.

5. Elastic fluid condensing apparatus comprising a plurality of condenser units, each of said units including a condensing part and an aftercoolcr part, a header for supplying elastic fluid to said condensing parts of said-condenser units, a reservoir for receiving condensate from said condenser units. conduit means for connecting said reservoir with each of said units, means for limiting the flow of elastic fluid to the condensing part of one of said condenser units. a conduit extending from said reservoir to the condensing part of said one unit for venting said reservoir, an extraction conduit for conveying uonwondensaoles from the aftercooler parts of said condenser units, means for reducing the pres sure in said extraction conduit, connections between said extraction conduit and said aftercooler parts including means for maintaining the pressure in said conduit lower than the pressure obtaining in any of said plurality of condenser units.

6. Elastic fluid condensing apparatus comprising a plurality of condenser units, a reservoir for a receiving condensate from said condenser units,

conduit means for connecting said reservoir with each of said units, conduit means connecting said reservoir with the inlet of at least one of said condenser units, and a header for supplying elastic fluid to the inlets of the other of said condenser units.

'7. Elastic fluid condensing apparatus comprising a plurality of condenser units, a drainage conduit connected to said condenser units for conducting condensate therefrom, means including a conduit communicating between the inlet of one of said condenser units and said drainage conduit adjacent the outlet thereof, and conduit means for connecting the inlets of the remainder of said condenser units to a source of elastic fluid to he condensed. 1

8. Elastic fluid condensing apparatus comprising condenser having several sections, conduit mea. for supplying elastic fluid to be condensed to said condenser, a reservoir, conduit means for draining the condensate from said condenser into said re crvoir above the liquid level therein, means for restricting the quantity of elastic fluid supplied from said supply conduit means to one section of said condenser, and conduit means connecting the reservoir above the liquid level therein with the inlet of said one condenser settion.

9. Elastic fluid condensing apparatus comprising a first condenser unit, conduit means for supply-in elastic fluid to be condensed to said first unit, a reservoir, conduit means for conducting the condensate from said first unit to said reservoir, a second condenser unit, conduit means connecting the upper portion of said reseiwoir to the vapor inlet of said second condenser unit, and conduit means for draining said second condenser unit to said reservoir.

10. Elastic fluid condensing apparatus comprising a plurality of condenser units, a reservoir, conduit means connecting said condenser units with said reservoir above the liquid level therein for draining condensate from said condenser units to said reservoir, means including a conduit connected between said reservoir above the liquid level therein and the vapor inlet portion of one of said condenser units for creating a suction upon the outlet of said condensate drain conduit into said reservoir, and conduit means for connecting the inlets of the remainder of said condenser units to a source of elastic fluid to be condensed.

11. In combination, a condenser unit, conduit means for conducting elastic fluid to be con-'- denscd to said unit, a condensate reservoir connected ahove'the condensate level therein to said unit for receiving the condensate therefrom, a second condenser unit. conduit means connecting the portion of said reservoir above the condensate level therein with the vapor inlet of said second condenser unit, conduit means for draining the condensate from said second condenser unit to said reservoir below the condensate level therein.

ALAN HOWARD. 

